


An Intimate Venture

by SoloShikigami



Category: Undertale (Video Game)
Genre: First Time, Loss of Virginity, M/M, Underfell Sans (Undertale), Underswap Sans (Undertale)
Language: English
Status: Completed
Published: 2020-05-02
Updated: 2020-05-02
Packaged: 2021-03-02 01:40:35
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,007
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23963257
Author URL: https://archiveofourown.org/users/SoloShikigami/pseuds/SoloShikigami
Summary: Red and Blue have been dating for a while, the both of them waiting on taking their relationship to the intimate level. Blue doesn't want to wait anymore, and while Red is pleased, he is taken by surprise. Being the more experienced one, Red wants to be sure he makes it a night Blue won't ever forget.
Relationships: Sans/Sans (Undertale)
Comments: 3
Kudos: 49





	An Intimate Venture

**Author's Note:**

> Written for SuperShadic for donating to a friend ^_^ Originally posted in July of 2018

Red paused in the middle of slurping up his noodles, staring at his boyfriend across the table, the translucent noodles dangling from his mouth.

“Really, now, Red,” Blue huffed. “It’s bad enough that you slurp, but at least finish slurping!”

A blush had formed over Blue’s face, but not out of embarrassment. Red bit the noodles, the remainders falling back into the broth. He glanced around the restaurant, filled with patrons who were busy eating their own bowls of pho to notice what Blue had proposed.

“R-really?” Red murmured, his gruff voice almost masking he small stutter.

“Absolutely!” Blue said with a smile as he reached over and put his hand over Red’s. “I’ve been wanting to for a while, just didn’t have the opportunity lately to speak up. Mweh, heh, I also kind of expected you to initiate it!”

Red’s blush deepened, and while he turned his hand up to hold Blue’s, he looked away in an almost shy fashion. It made Blue frown a little.

“It’s okay if you think it’s too soon, you know?” Blue said gently. “You know I’m not going to force you.”

“Well, yeah, no, of course not,” Red said, clearing his throat and sitting up straight, trying to pull his rough confidence up. “Heh, like you could force me to do anything. I just didn’t wanna scare you or nothin’, you know?”

“Scare me?”

“I’m kind of a big guy, you get me?” Red said, leaning forward and grinning at Blue with a leer.

“We’re made of magic, you dork,” Blue said with a giggle. “We can make whatever we want!”

“Maybe,” Red said, backing off a little. “Still, uhm,” Red’s confidence wavered slightly as he toned down his flirtations. “Fuck, I don’t even know like, what you’ve experienced.”

“Mmm, not much,” Blue said, putting his elbow on the table and leaning his head in his hand thoughtfully, swinging his feet. His other hand still held onto Red’s, his thumb brushing over his knuckles. “A few monsters and I have fooled around before, but nothing that intimate. A few touches under clothing, some kisses and such in paces other than one’s mouth.”

“Ever have anyone go down on you?”

“What?”

Red couldn’t help the smirk and he leaned forward, crooking the fingers on his other hand to entice Blue to move closer.

“Anyone ever suck your cock, baby Blue?” he asked in a quiet tone.

“Red!” Blue shoved his shoulder, blushing furiously as he also glanced around to see if anyone had heard or been listening.

Red broke out in a hearty laugh while Blue tried to not sputter in embarrassment.

“C’mon, let’s grab the check and get out of here. I think we have quite the conversation ahead of us.”

* * *

Their walk home had not only been conversation about their past experiences, but also some teasing and flirting, especially from Red. By the time they got back to their shared apartment, Red was so turned on by Blue’s responses and blushing and stammering remarks that he all but slammed the smaller skeleton against the door to close it, kissing him deeply, his hands running just about everywhere he could touch.

Blue made small whimpering sounds, his body moving into Red’s touches, unable to do much other than grip Red’s jacket and kiss him back as fiercely as he could.

“Mmm, wait, wait,” Blue gasped as the kiss broke.

“Are you okay? I didn’t hurt you, did I?” Red asked, backing away immediately.

“Oh, no, no, sorry, no, you didn’t hurt me,” Blue said quickly, keeping his grip on Red’s jacket. “I want to touch you, too, and it’s a bit hard from this position.”

Blue’s hands slid down from Red’s jackets to the hem of his shorts, thumbs dragging along the elastic, pushing it down slightly so he could rub his fingers along bare bone.

“Oh, uhm, okay, yeah,” Red nearly stammered. “I guess, uh, how’s about we go into the bedroom?”

“Sure,” Blue smiled and leaned in to kiss him gently, before taking his hand and leading the way.

_Fuck, he’s so cute, how did I get so lucky?_ Red thought to himself. _I gotta make this good for him, he deserves it._

Once they were in the bedroom, Red shut the door behind him for good measure, and Blue pulled him into the room more and brought him into another kiss, this one gentler.

Red let Blue do what he wanted. The small hands pressed against his ribs, then moved up under the shoulders of his jacket and pushed it off. Red wriggled his arms a bit so that the heavy leather jacket fell off behind him. Blue smiled, deepening the kiss as his hands began to explore, moving along his ribs and spine over his t-shirt, then moving down, gathering the hem and pushing the worn fabric up, but the height difference made it a little difficult for Blue to push it up and over Red’s head.

“Hang on, Blue, I got it,” Red said with a chuckle, grabbing onto the gathered fabric and pulling it over his head, tossing it aside.

Before Red could put his arms down, Blue leaned in to lick across Red’s clavicle, his fingers brushing over the edges of his floating ribs and down his spine. Red grunted in approval, one hand stroking the top of his head in encouragement.

“Should I keep going?” Blue asked.

“Sure, dollface, you can do whatever you want,” Red said.

Blue smiled, his hands moving to the top of Red’s shorts, pushing them down further than before, but then his mouth stuttered when he realized that the shorts weren’t really moving down. Glancing between Red’s legs, Blue could see that Red was quite turned on. Not to be discouraged, he took a moment to pull the fabric around and then he could very clearly see why he had some trouble.

While Blue pointed out during their dinner that being magic-based monsters, they could control what they formed and how big they could be, he also knew that Red was lazy.

That being said, Red’s warning came back to the front of Blue’s mind.

“You okay, there, precious?” Red asked.

“Oh, uhm, yes, very, yes, I’m okay,” Blue said quickly, unable to take his eyes off of the thick, long rod of magic. His mind was racing; was this really going to fit inside of him? He was a good deal smaller than Red as it was, and while their magic was pliant, he wasn’t so sure about their bone structure.

“Are you?” Red said, sounding a little concerned. He reached up and stroked Blue’s head.

Blue nodded.

“What do you want to do with it?”

Blue couldn’t bring himself to answer, so instead he gingerly wrapped his hand around the thick girth, squeezing lightly, experimenting.

“Oooh, that’s nice,” Red sighed.

Blue squeezed a little harder and started to slowly stroke Red, glancing up now and then to make sure he was doing it right. Red smiled, sighed, and caressed Blue’s skull to reassure him.

“Uhm, Red, should I, uhm, suck on it?” Blue asked timidly.

The question seemed to snap Red out of the soft headspace he found himself in, and the reality of the situation had slammed back into him like a sledgehammer.

“Oh, no, Blue, not right now,” Red said, reaching down to put his hand over the one Blue had around his dick, bringing it up to kiss the back of it. “Do me a favor, babe, and go sit on the bed.”

“Okay!”

Blue nearly skipped over to the bed and hopped up onto the edge with a small squeal. He smiled at Red, swinging his legs.

Red faltered as he realized that this was Blue’s first time being so intimate with someone else. He was going to be his first, the one to take his virginity, the first one to make him feel things and connect with someone in the most intimate way possible.

He started to wonder if he could do it.

“Red?”

Again, Blue broke Red out of his thoughts. He looked over at the little skeleton sitting on the bed, tried to swallow his concerns and focus on making Blue feel good. He pulled his shorts back up for now and moved over to Blue, bending over him to kiss him.

“Hey, you okay?” Blue asked when Red broke away and pressed their foreheads together.

“Yeah, yeah, I’m fine.”

“You’re trembling. Please talk to me?”

Red sighed, reaching up to cradle Blue’s face, kissing him briefly.

“I just want to make this good for you, is all,” Red murmured. “I mean, I can’t believe you’re with me to begin with. You must have had monsters throwing themselves at you before you met me.”

“Oh, Red,” Blue laughed, putting his hands over Red’s and looking him in the eye. “I love you so, so much. I can’t believe that you’re with me, either. Most others find my energy intimidating or annoying, much like how people mistake your own rough and tumble nature, meanwhile you are one of the sweetest, most loving monsters I have ever come across.”

Blue leaned up into Red to kiss him again.

“But are you absolutely sure about this?” Red asked.

“Please, Red,” Blue murmured, his pupils slowly switching from the usually stars to hearts. “I don’t want to share this with anyone but you. I want you, I need you, I love you.”

“Okay,” Red breathed. “I love you, too, Blue. I’m going to go slow, so please tell me if you need me to stop. You promise?”

“Yes, Red, I promise.”

Red nodded and pressed in to kiss Blue again. Once the two relaxed again, Red moved down a bit to lick and nibble at his neck while his hands slipped down to Blue’s shorts. He gently pushed them off Blue’s hips, moving to kneel on the floor so he could pull them off his legs. He looked up at Blue with a smile, rubbing along his femurs. Blue smiled down at him with a reassuring look and he nodded.

Slowly, Red pushed Blue’s legs open, and was greeted with Blue’s magic as it finished forming into a soft-looking pussy.

“Blue, you look wonderful,” Red breathed. “So beautiful. I bet you taste wonderful.”

“Please, Red,” Blue sighed, wriggling a little.

Red’s hands slid up Blue’s legs, his thumbs brushing along the inside and sliding along the outside of the thin lips of his vulva. Carefully pulling them aside, he took in the soft folds and the small hole.

_Crap, am I going to be able to fit in him?_ Red wondered.

“Red,” Blue whined, wiggling again.

“I gotcha, baby,” Red said, moving in closer.

Blue blinked. “Red, what are you- w-w-w-whoa!”

Blue shivered as Red’s tongue took a long, slow swipe from the small opening, through his folds, and up to the small nub of magic that was more sensitive than the rest of him. Red did it again, making Blue gasp, and the third got Blue slamming his hands over Red’s.

“You okay?” Red asked.

“Yes, yes, oh stars, yes,” Blue moaned.

“Okay.”

Red continued to gently and slowly lap at Blue’s pussy, flicking his tongue over his clit, drawing different patterns to find out which spots drove Blue wild. He noticed some fluid beginning to leak out of Blue’s entrance and he decided to start dipping the tip of his tongue inside.

Blue cried out, bending over Red. Red pulled back but Blue put a hand on the back of his head.

“No, please, don’t stop, I’m fine,” Blue assured him.

Red nodded and continued. He pressed his tongue in a little further, his fingers rubbing along and inside the folds, brushing across his clit each time he thrust his tongue in. Blue’s magic began to relax and widen to accept Red’s questing tongue, and he could feel Blue getting wetter. Blue’s legs trembled on either side of him, and his whimpers grew louder as he began trying to move into that questing tongue.

It was all a huge turn-on for Red, hearing Blue slowly falling apart, pleased at the pants and groans that came with his motions, and while he was hard before, it was growing painful now.

“Red, please, I, I need more,” Blue begged.

“Oh?” Red asked.

“Yes, please, I, I don’t know what, but I need more, I need you, please, please, please!”

“Okay, but again, I’m kinda big, so I want to prep you a bit first.”

Red pushed in two fingers, drawing a small cry from Blue.

“More, please, I need more!”

Red pressed a third finger in, gently pumping in and out, spreading his fingers a little to open him up a bit more, but Blue seemed to have other ideas as his wriggling was making it all nearly impossible for Red to continue.

“Red! Please!” Blue cried.

“All right, baby, all right,” Red said, moving up to kiss Blue. “Lay back on the bed.”

Blue scrambled back, pulling off his shirt as Red took off his shorts. He climbed onto the bed, his erection bobbing heavily between his legs and he crawled over Blue, looking down at the smaller skeleton, whose face was flushed and his face was a mix of arousal and frustration.

“I don’t want to hurt you, so we’re going to go slow, so take it easy, okay?” Red said gently.

“All right.”

“And you tell me if it hurts, we can stop, I can still make you feel good, no problem.”

“I know, but, Red, please!”

“I don’t want you to feel pressured.”

“I don’t.”

“But just in case, I-!”

“Red!” Blue shouted with a laugh. “Red, I want this, I want you, and I couldn’t ask for a better bed partner. I trust you. I promise I’ll tell you if I’m not enjoying myself, however I am, more than I could ever have imagined. Take me, Red, please?”

Red nodded, reaching down to rub his cock against Blue’s pussy, which was nearly dripping, making sure he was good and wet before pressing the head against the entrance, and after another nod from Blue, he slowly pushed inside a little.

“Wowzers!” Blue gasped at the intrusion. “No, no, keep going, just, yeah, slow.”

Red nodded and continued, pausing after each bit to allow Blue to adjust and get accustomed, trying his best to keep his own patience under control because, stars damn it, did Blue ever feel good.

“K-keep going, I’m okay,” Blue panted.

Red chuckled. “I’m all the way in, darling.”

Blue opened his eyes and glanced down to where the two were joined, Red’s magic making a purple glow from inside Blue.

“Oh, my,” Blue breathed. “This feel really nice. But, I have to say, I’m not completely sure what the big deal is?”

“What do you mean?”

“Well, people say how sex is mind-blowing, and talked about these orgasm things that would happen, and… why are you laughing?”

“Hold on, Blue.”

Red slowly began to pull out, and when he was about halfway and Blue was about to ask, he pressed back in again, a little quicker and firmer this time. Blue arched and cried out beneath him.

“Oh, stars, do that again!”

“Heh, sure thing doll.”

Red began at a slow and even pace, wrapping his arms around Blue to press their bodies together as close as possible. Blue seemed to like this, as he, too, also wrapped his arms around Red. Red picked up the pace, Blue wrapped his legs around his hips and began arching into him.

“Feel good?” Red panted.

“Oh,God, yes, yes,” Blue answered in a moan. “I’m starting to feel funny, like something’s going to burst!”

“Yeah, I can feel you tightening, you’re gonna cum, and it’s going to feel so good,” Red smiled down at him. “Relax, Blue, and cum for me.”

Red picked up the pace even more, feeling his own peak approaching as Blue’s walls fluttered and massaged his cock.

“Red, Red,” Blue began chanting.

“That’s it, love, just let it go.”

Blue’s whole body began to shake, his eyes hazy, when suddenly he stilled, body tightening as he cried out.

“Good boy, good boy,” Red chanted, licking his neck, slowing a little to ride out Blue’s orgasm. “I’m almost there, fuck, you’re so beautiful.”

Blue continued to shake, continuing to chant Red’s name, until Red pressed in deep and growled into Blue’s neck, his cock spurting hot magic into Blue, making him moan. They were still, panting for breath, their magic still formed together, then Red pulled back to look into Blue’s face.

“Blue, you okay?” Red asked.

“Yeah, that, that was amazing,” Blue murmured. He pulled Red into a kiss, and Red kissed him slow and deep.

They lay on the bed, kissing gently, murmuring words of praise and gratitude as their magic slowly dissipated, leaving only slowly remnants of their love-making behind.

“We should probably shower,” Blue murmured, noticing their shared fluids were getting sticky on their bones.

“Nah, we can sleep like this,” Red said.

“Oh, no, come on, lazybones,” Blue said.

After some more cajoling, the two were in the shower, Red making enough puns and lewd remarks to get Blue blushing, they switched out their blanket for a simple sheet and snuggle together in their bed.

“Red?”

“Yeah?”

“Thank you, again, for being my first.”

“And thank you, again, for trusting me to be your first,” Red said, kissing the top of Blue’s skull. “And thank you for putting up with me being all nervous about it. It’s just that I wanted to make sure you would have a good time with me.”

“How could I not?”

“Eh, I’m just paranoid, I guess.”

“Like I said before, Red, you put up a tough front, but I would like to think I know you better. You are very sweet, gentle, and caring with me, and that’s been shown more-so this evening.”

“I love you, Blue.”

“I love you too, Red.”

**Author's Note:**

> Like what you read? Please check out my social media for more fun!  
> [ My Tumblr](https://soloshikigami.tumblr.com/)  
> [ My Twitter](https://twitter.com/SoloShikigami)


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